NVMe: Use a symbolic name to represent cancelled commands instead of 0
I have plans for other special values in sync_completion. Plus, this
is more self-documenting, and lets us detect bogus usages.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 60c3786..802d763 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -31,6 +31,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pci.h>
+#include <linux/poison.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/types.h>
@@ -158,15 +159,17 @@
}
/* If you need more than four handlers, you'll need to change how
- * alloc_cmdid and nvme_process_cq work. Also, aborted commands take
- * the sync_completion path (if they complete), so don't put anything
- * else in slot zero.
+ * alloc_cmdid and nvme_process_cq work. Consider using a special
+ * CMD_CTX value instead, if that works for your situation.
*/
enum {
sync_completion_id = 0,
bio_completion_id,
};
+#define CMD_CTX_BASE (POISON_POINTER_DELTA + sync_completion_id)
+#define CMD_CTX_CANCELLED (0x2008 + CMD_CTX_BASE)
+
static unsigned long free_cmdid(struct nvme_queue *nvmeq, int cmdid)
{
unsigned long data;
@@ -177,9 +180,10 @@
return data;
}
-static void clear_cmdid_data(struct nvme_queue *nvmeq, int cmdid)
+static void cancel_cmdid_data(struct nvme_queue *nvmeq, int cmdid)
{
- nvmeq->cmdid_data[cmdid + BITS_TO_LONGS(nvmeq->q_depth)] = 0;
+ nvmeq->cmdid_data[cmdid + BITS_TO_LONGS(nvmeq->q_depth)] =
+ CMD_CTX_CANCELLED;
}
static struct nvme_queue *get_nvmeq(struct nvme_ns *ns)
@@ -396,8 +400,8 @@
struct nvme_completion *cqe)
{
struct sync_cmd_info *cmdinfo = ctx;
- if (!cmdinfo)
- return; /* Command aborted */
+ if ((unsigned long)cmdinfo == CMD_CTX_CANCELLED)
+ return;
cmdinfo->result = le32_to_cpup(&cqe->result);
cmdinfo->status = le16_to_cpup(&cqe->status) >> 1;
wake_up_process(cmdinfo->task);
@@ -480,7 +484,7 @@
static void nvme_abort_command(struct nvme_queue *nvmeq, int cmdid)
{
spin_lock_irq(&nvmeq->q_lock);
- clear_cmdid_data(nvmeq, cmdid);
+ cancel_cmdid_data(nvmeq, cmdid);
spin_unlock_irq(&nvmeq->q_lock);
}